For better understanding the principle of the present invention and for introducing terminology used in the description, it would be advantageous to briefly explain the structure and operation of the radiator and the radiator cooling system.
The radiator is a device designed to dissipate the heat, which the coolant has absorbed from the engine. It is constructed to hold a large amount of a cooling liquid or coolant in tubes or passages, which provide a large area in contact with the atmosphere. As the coolant passes through the radiator during operation of the engine, it loses its heat to the airstream, which passes around the outside of the tubes. Normally, the cooling system of a vehicle has a clear plastic container, which is also known as a coolant reservoir or a coolant overflow bottle (hereinafter referred to as coolant reservoir). The coolant reservoir has marked lines that indicate the upper and lower allowable levels of the coolant in the cooling system. This coolant reservoir is connected to the coolant supply tube, which is also known as a siphon tube from the radiator and provides extra storage space for the coolant when it expands. As the engine heats up, the coolant inside it expands. Without the coolant reservoir, the coolant would flow out of the overflow tube and be lost from the cooling system.
Since a vacuum is created in the cooling system when the engine cools, the vacuum causes some of the coolant in the coolant reservoir to be sucked back into the system. The suction is carried out through the aforementioned coolant supply tube. In known radiator cooling systems the coolant supply tube from the radiator is connected to the coolant reservoir through the wall of the reservoir in its upper part or through a coolant reservoir cap which is used for adding the coolant to the cooling system when necessary. The end of the coolant supply tube inserted into the reservoir extends down to the point close or below the indicator of the lower allowable level.
The coolant reservoir may also be provided with an overflow tube located close to the top of the reservoir, e.g., in the coolant filling neck, for the overflow of the coolant when it expends to the level above this overflow tube, and with a drain tube at the bottom of the reservoir for draining the coolant from the reservoir, e.g., for cleaning the interior of the reservoir.
Because a cooling system with the coolant reservoir is virtually a closed system, the coolant can flow between the system and the coolant reservoir as it expands and contracts. This way, no coolant is lost if the system is functioning properly. The advantage of the coolant reservoir is that while the level of coolant contained in it rises and falls, the radiator is always full.
The radiator is provided with a fan surrounded by a shroud. The fan cools the cooling liquid while it circulates through the radiator's channels.
There exist a variety of arrangements for placing the coolant reservoirs in the vicinity of the radiator. Normally the coolant reservoir is attached to a vehicle body in the engine compartment and is located separately from the radiator or shroud. However, some vehicle models have the coolant reservoir removably connected to the fan shroud.
For example, U.S. Pat. No. 6,523,507 provides a fan shroud for an internal combustion engine that includes a snap-on detachable overflow bottle. The fan shroud has a fan opening and a unitary bottle mount with a deflectable bottle clip with a latch end that engages a groove in the overflow bottle. The mount includes an opposite side with an inwardly directed locking surface that engages a recess in a side face of the overflow bottle. The overflow bottle is held upright and secured to the fan shroud by snapping it into the bottle mount. A disadvantage of the design disclosed in the aforementioned patent is that it requires the use of additional snapping fasteners that can get loose under the effect of vibrations that normally occurs in the engine compartment when the vehicle is running. As a result, the coolant reservoir will be subject to vibrations that will generate a noise. Another disadvantage of the device of U.S. Pat. No. 6,523,507 is that the coolant is supplied to the coolant reservoir through a separate coolant supply tube that is inserted into the reservoir through the sealing unit. In other words, the arrangement requires the use of additional parts, such as tubes, seals, snapping elements, etc., is complicated in the manufacture, and costly in production and assembling.
The authors of U.S. Pat. No. 6,523,507 criticize the construction of fan shrouds molded integrally with the coolant overflow bottles stating that in the case of puncture or other damage of the bottle the whole shroud has to be replaced. It is understood, however, that the coolant overflow bottle located in the engine compartment and protected by the vehicle hood will never be punctured unless the vehicle is seriously damaged in an accident. If this happens, the engine has to be removed from the vehicle anyway and the shroud has to be removed as well.
U.S. Pat. No. 5,971,062 discloses a fan shroud, which is made integrally with at least one chamber for storage of a liquid or with several chambers for storage of several liquids, which may be under pressure and used with a vehicle. To facilitate handling pressure, the storage chamber includes a plurality of individual storage modules which are interconnected by a plurality of fluid flow channels so that the total storage capacity of the chamber is the sum of the storage capacity of the modules and interconnecting fluid flow channels. The modules and channels are made by bringing the front and back walls of a blow molded fan shroud into contact with each other to define there between channels and modules. The shroud comprises several such chambers and may be used to house engine coolant, power steering fluid or other fluids. In addition, the fan shroud can include chambers for storing fluids, which are not necessarily under pressure such as windshield washer fluid and the like.
A disadvantage of the arrangement shown in U.S. Pat. No. 5,971,062 is that it has a very complicated construction, which is expensive to manufacture. There is no indication in the description of the above patent to the way of checking the level of the coolant in the coolant reservoir of the device of the invention. It can be assumed, however, that since the reservoir and the shroud are blow-molded as a single piece, they are made from the same material. The shroud is normally molded from a non-transparent material and therefore the level of the coolant in the coolant reservoir is presumably checked by opening the filling cap, which is inconvenient.
U.S. Pat. No. 6,189,492 describes an automotive fan shroud that is molded integrally with two compartments, one for the coolant and another for windshield washing liquid. The compartments are closed from above by separate covers through which liquids are supplied into the respective containers. Since the compartments are molded from the same nontransparent material as the shroud, the level of the liquids in the compartments cannot be observed unless the covers are removed. Furthermore, the use of additional tubes and covers that require means for securing them in place makes the construction expensive in manufacture and assembling.
Typical engine cooling systems of vehicles are shown in a series of Automotive Repair Manuals for vehicles of various models, which are available in many automotive parts stores. For example, a cooling system for Mitshubishi Pick-ups 1983 through 1996 and Mitsubishi Montero 1983 to 1993 (shown in page 3–4, Chapter 3 of the Mitsubishi Puck-ups & Montero Automotive Repair Manual by Larry Warrenm et al. issued by Haynes Publishing Group) contains a coolant reservoir with a coolant supply tube and an overflow tube connected to the reservoir through a coolant filler cap. The reservoir is installed separately from the fan shroud. Such an arrangement entails all previously mentioned drawbacks, i.e., connection of the feeler tube and the overflow tube through seals and securing fasteners. The feeler cap has a complicated construction. The reservoir has to be attached to an internal part of the vehicle body inside the engine compartment with the use of additional fasteners which can get lose under the effect of shocks and vibrations to which a vehicle is normally subject during running. Location of the coolant reservoir separate from the shroud and the need for attachment with fasteners increases the cost of manufacturing and assembling.